A Highly Dependable Computing Architecture for Safety-Critical Control Applications

. More and more technical systems are supervised, controlled and regulated by programmable electronic systems. The dependability of the entire system depends heavily on the safety of the embedded software. But the technological trend to entrust software with tasks of growing complexity and safety relevance conflicts with the lacking acceptance of rigorous proofs of software safety. Based on an international standard for higher level programming languages for programmable logic controllers (PLC, IEC 1131-3), a mathematically based method for validating the behavioral correctness and the functional safety of graphical designs of safe-critical control applications is introduced. The design elements taken from a domain specific module library are proven correct and safe only once. The functional correctness and satifaction of safety requirements of new application graphical programs can then be shown effectively by reference to the proven properties of the library components used. This app..